What odds on Boris Johnson losing the Supreme Court case?

Retired Supreme Court Justice Lord Sumption has predicted that his former colleagues would probably hold that the prime minister’s prorogation of parliament was not justiciable. That was my view too. But having read Lord Pannick’s written case for Gina Miller, the lead appellant, I have changed my mind. I now think there is a fair chance that the decision will go the other way and reverse the unanimous decision of the Divisional Court given on 6 September by the Lord Chief Justice, the Master of the Rolls, and the president of the Queen’s Bench Division.

Lord Pannick’s 25-page argument (see the Supreme Court’s website) proceeds in stages:

• The legal principle of parliamentary sovereignty requires that the executive must comply with the enacted will of Parliament. It is implicit in that legal principle that there must be legal limits on the power of the executive to prevent Parliament from sitting so that